HYALONEMA (PRIONEMA) AGUJANUM. 251 



Hyalonema (Prionema) agujanum, sp. nov. 



tenuis, var. nov. Form A. 



Plate 72, figs. 17-21, 23-2.5, 27; Plate 73, figs. 1-6; Plate 74, figs. 1-5, 8; Plate 75, figs. 1-13, 15, 17, 

 19-27, 29-37; Plate 76, figs. 1-7, 11, 12, 15-36. 



tenuis, var. nov. Form B. 



Plate 72, figs. 16, 22, 26; Plate 73, fig. 7; Plate 74, figs. 6, 7, 9; Plate 75, figs. 14, 16, 18, 28; Plate 76, 



figs. 8-10, 13, 14. 



lata, var. nov. 

 Plate 77, figs. 1-10; Plate 78, figs. 1-15. 



I establish this species for five specunens collected off northern Peru, near 

 Aguja Point, at Station 4656 on 13 November, 1904; 6° 54.6' S., 83° 34.3' W.; 

 depth 40G3 m. (2222 f.); they grew on fine, green mud mixed with gray ooze; 

 the bottom-temperature was 35.2°. The specific name refers to the locality. I 

 distinguish two varieties in this species, one comprising four specimens, with 

 narrow, one comprising one specimen with broader serrated amphidisc-anchors. 

 In view of the difference in the anchor-breadth of these amphidiscs, I name the 

 former tenuis, the latter lata. One of the four specunens of var. tenuis differs 

 somewhat from the other tliree; I therefore distinguish two forms, A and B, in 

 this variety. Form A comprises three specimens, form B one. 



Shape and size. All the specimens (Plate 75, figs. 28-30; Plate 78, fig. 4) 

 are inverted, conical, and more or less flattened laterally. The better preserved 

 ones have a broad and shallow depression on their upper face and a stalk which 

 arises from the lower narrow end. I consider the apical depression a gastral 

 cavity. In one specimen the remnant of a gastral cone is visible in its centre. 

 The specimens are 19-29 nmi. long, 23-30 mm. broad, and 8-16 mm. thick. 

 The stalks present are broken off quite short. The longest is 24 imn. long. A 

 few Palythoa polyps are attached to the proximal part of the stalk just below 

 the point where it arises from the body (Plate 75, figs. 29, 30; Plate 76, fig. 7). 



The colour of all the specimens in spirit is brown. 



The skeleton. The dermal and gastral surfaces are entirely covered w»fth a 

 dense fur composed of the distal rays of pentactme pinules. In the spicule- 

 preparations a good many diactine pinules were found. These in all probability 

 occupy the margin of the apical (gastral) cavity. In the subdermal and sub- 

 gastral zones radial pentactines and paratangential rhabds are met. Similar 

 rhabds, hexactine megascleres, and microhexactines occupy the interior. Here 



